# recursion is function calling functioin # sum of 10 num is sum of 9 + 1 # sum of 9 num is sum of 8 + 1 # sum of 2 num is sum of 1 + 1 # sum of 1 num is sum of 1 + 0 def summing(n): answer = 0 if n<=0: return 0 else: summing(n-1) for i in range(n+1): answer = answer + i print(answer) callme = summing(5)